Sheet-metal pipe



(No Model.)

0. L. HART. SHEET METAL PIPE.

No. 409,196. Patented Aug. 20, 1889.

rrnn States Patent @rricn.

CHARLES L. HART, OF BROOKLYN, NElV YORK.

SHEET-METAL PIPE.

SPECIFICATION forming part of Letters Patent No. 409,196, dated August20, 1889.

Application filed December 19, 1888. $eria1N0. 294,184. (Nomodeh) To allwhom it may concern:

Be it known that I, CHARLES L. HART, a citizen of the United States,residing at iroolclyn, Kings county, New York, have invented certain newand useful Improvements in Sheet-Metal Pipes, fully described. andrepresented in the following specification and the accompanyin drawings,forming a part of the same.

This invention consists in a sheet-metal pipe formed in two or morelongitudinal sections united by longitudinal twisted seams.

It also consists in certain n'iodilications hereinafter fully set forth.\Vhen formed with standing spiral seams, the appearance of the pipe isnot only novel and ornamental, but the standing spiral. seams operate tobrace and stiffen the pipe in a very remarkable degree.

In all the pipes heretofore manufactured with spiral seams the pipe hasbeen constructed with a single spiral seam and formed by wrapping ablank transversely to the axis of the pipe and securing one edge of theblank upon the opposite edge of the same blank when lapped spirallythereon. Such a pro cess may be continued indefinitely to form anendless pipe; but to form a pipe in such manner requires specialmachinery adapted to wind the blank and secure its overlapped edgestogether, and the object of my present invention is to avoid the expenseof such special machinery in forming a pipe with a spiral scam. I effectsuch object by first forming the pipe of straight longitudinal sectionsof convenient length united by longitudinal seams and then twisting thewhole when seamed together.

The straight longitudinal sections which are required to form a pipewith straight longitudinal seams may be readily shaped with outexpensive dies in the ordinary cornicebrake found in the shops of alllarge workers in sheet metal, and they may also be formed in suitablestamping or shaping presses by providing dies of suitable profile andpressing the sheet-metal blanks between them. The pipe may thus be madeand seamed longitudinally with very little expense, and may then betwisted bodily to form the twisted seam thereon by merely graspin thetwo ends of the pipe and turning them in opposite direetions.

The invention will be fully understood by reference to the annexeddrawings, in which Figure 1 is a view of a pipe provided with straightlongitudinal seams prior to the twisting operation, the view showing theedge of the standing seam g. Fig. 2 a side viewof the same pipe withstanding seam g spirally twisted one-half a revolution. in the length ofthe pipe. Fig. 3 is an edge view of the same pipe with one end of thepipe tapered and a portion of the standing scam removed and the otherend flared and the standing seam flattened down. Fig. at is an end viewof a die adapted to twist such pipe. Fig. 5 is a longitudinal sectionacross the center of the same with one end e of the pipe fitted therein.Fig. 6 is an end view of the two sections of a pipe shaped ready forseaming. liig. 7 is an end view of the same pipe with the seam closedand bent down upon the pipe, and Fig. 8 is an end view of a pipe formedin three longitudinal sections with three standing seams. Figs. 6, 7,and S are drawn upon a larger scale than the other figures.

In Fig. (3 the sections of the pipe are shaped each to embrace one-halfits circumference, the sections a and I.) being provided each with alongitudinal radial flange a at one edge and with a bent flange 1') atthe opposite edge. The sections are thus similar, and any number ofsimilar sections may thus be used in forming the pipe.

Fig. 7 shows the sections united together with the flange I) closed overthe flange a and both bent down over the pipe, as in double seaming. I

In Fig. 8 the pipe is shown formed in three longitudinal sections 3,19,and s united by similar seams, but the seams g projecting radially fromthe pipe.

In Figs. 4 and 5 the die is shown provided with handles a and formedwith. a conical bore (1, adapted to partially admit the end of the pipee. Longitudinal grooves fare formed in the sides of the bore to admitthe standing seams g. The pipe made in the following manner:

Sheetmetal section -blanl s of suitable length and width are prepared toform the required sections for one length of pipe, and each is shapedatits edges to form a seam in conjunction. with the edges of theadjacent sections. The longitmlinal. seams are then closed sufficientlyto hold the sections together during the twisting operation, and theseams are, after the pipe is twisted, permanently closed to hold thesections in their twisted position.

It will be readily perceived by comparing Figs. 1 and 2 that the spiralseam in Fig. 2 is necessarily longer upon the same pipe than thestraight seam in Fig. l, and it will therefore be obvious that in thetwisting operation one or more of the flanges a must slidelongitudinally upon certain of the flanges b an amount corresponding tothe difference in the length of the straight and spiral seams, and thatthe end of each section will assume an angle with the axis of the pipe,owing to the twisting of each section-blank around such axis. All theseams are not therefore rigidly closed prior to the twisting operation,as such closing would cause a great resistance to such sliding movementof the flanges, but part only of the seams, as the seam g in Fig. 2, areclosed rigidly before the pipe is twisted to hold the sections firmly intheir twisted position.

It will be noticed in Fig. 2 that the ends of the blanks a and Z2coincide upon. the closed seam g, thus forcing the sliding of theflanges to occur upon the seam g, at the ends of which the displacementis obvious. It will also be understood that the metal in the flanges aand I) is materially changed in form during the twisting operation, andre ceives a permanent set to such form before and during the finalclosing of the seams. It is well known that longitudinal blanks bent inthe form shown in Fig. 6 are in practice, when formed, more orlesswarped or buckled, so that the flanges a and Z) upon the opposite edgesof the section a or I) would not lie in the same flat plane. The seamingof the sections together brings the flanges a and b into'contact withoutmaterially affecting the tendency of the sections to warp or buckle, anda perfectly straight pipe is not therefore produced by the mere joiningof the seams. I have, however, discovered that the twisting operationserves to remove all the buckle from the pipe and to make it exceedinglystraight, while the set imparted to the respective sections and theseams formed upon their edges serve to hold the pipe permanently in suchstraight condition. By retaining the seams in a radial position upon thefinished pipe at the close of the final seaming operation, as shown inFigs. 2, 3, and S, the standing seam greatly re-enforces the .pipe inevery direction and imparts to it an unusual degree of strength andrigidity.

It will be understood by reference to Fig. 1 that the edges of thesections a and I) in the untwisted pipe are parallel with the axis ofthe cylinder or pipe which they form, the curvature of the metal beingtransverse at the edges to such axis, while an inspection of Fig. 3 willshow that the twisting operation entirely changes the cylindricalcurvature of the metal, so that the line of the curvature is notparallel with the edges of the sections, but at an angle t-hereto equalto the are through which thepipe is twisted.

The spiral seam formed upon the pipe in my invention is a much longerand more gradual spiral than could be formed by spirally winding asingle blank and securingits overlapped edges, and my construction isreadily distinguished from any pipe having a single spiral seam insteadof two or more, as in my invention.

The blanks for the sections may be formed with oblique ends, so thatwhen the pipe is twisted its ends will be at right angles to its axis.Then the standing seam is used, the pipe-lengths may be readily fittedtogether by flattening down or removing a portion of the seam at eachend and fitting the ends to enter one into the other, as is common withsheet-metal pipes, and shown upon the pipe in Fig. 3 at h and h.

It is immaterial how the pipes are twisted after seaming or how theseams are finally locked to hold the sections in their twisted position, and no means for locking the seams is therefore shown herein;

Having thus set forth my invention, what I claim is- 1. As a new articleof manufacture, a sheetmetal pipe formed in two or more longitudinalsections and having twisted seamsat the joints of the sections,substantially as herein set forth.

2. As a new article of manufacture, sheetmetal pipes in uniform lengthsformed in' two or more longitudinal sections and having twisted seams atthe joints of the sections, substantially as herein set forth.

8. As anew article of manufacture, a sheet- 'metal pipe formed in two ormore longitudinal sections and having twisted standing seams at thejoints of the sections, substantially as herein set forth.

4:. As anew article of manufacture, a sheetmetal pipe formed in two ormore longitudinal sections and having twisted standing seams at thejoints of the sect-ions, with the projection of the seam removed at theends of the pipe and the ends longitudinally flared and tapered to jointhe same in series, substantially as herein set forth.

5. As a new article of manufacture, a sheetmetal pipe formed in two ormore longitudinal sections united by longitudinal standing seams andhaving the sections and scams twisted and held in a twisted condition bythe locking of the seams, as and for the purpose set forth.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

CHARLES L. HART.

\Vitnesses:

ANSON O. KITIREDGE, HENRY OoLWELL.

